mysterious
/mɪˈstɪə̯.ɹi.əs/
Proposed by a contributor, not yet supported by evidence.
Sense 1
Meaning · English
Of unknown origin.
Adjective
Examples
He received a mysterious phone call this morning.
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01 via kaikki.org).
Sense 2
Meaning · English
Having unknown qualities.
Adjective
Examples
Our boss is a mysterious man who hardly ever meets with us.
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01 via kaikki.org).
Common questions
What does “mysterious” mean?
Of unknown origin.
Is “mysterious” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.